1. Field of the Invention
The present invention relates generally to the field of orthotic devices and appliances; more particularly to orthotic devices and appliances useful for restoring movement to connective joints (especially to elbow and knee joints) of a mammalian body (especially a human body); and still more particularly to orthotic devices and appliances used to reverse contractures due to immobility and neurological dysfunction.
2. Background Discussion
My prior U.S. Pat. No. 5,891,068, issued on Apr. 6, 1999 (which is incorporated herein in its entirety by specific reference), defines the term “orthotics” (quoting Webster's New Collegiate Dictionary) as “a branch of mechanical and medical science that deals with the support and bracing of weak or ineffective joints or muscles.”
As observed in such prior patent, orthotic devices and appliances (commonly referred to just as “orthotics”) have been utilized for many years by physical and occupational therapists, as well as certified orthotic fitters, to assist in the rehabilitation of loss of range of motion (LROM) of patients' joints and associated limbs or adjacent skeletal parts of patients' bodies. Thus, orthotics, as well as splints, have been designed both to maintain and to restore the range of bodily motion due to LROM. Such LROM may, for example, be caused by traumatic injury, joint or limb surgery, and/or contracture due to immobilization caused by neuromuscular disorders (e.g., stoke and closed head injury) and other disease processes that significantly limit a patients ability to use a joint for normal activities of daily living (ADL).
Two fundamentally different types of contractures exist which clinically should have two different treatment protocols. The difference in these two types of contractures is the basis for the clinical techniques and design of the orthotics of the present invention which will be described below.
A first one of these two fundamentally different types of contracture may be defined as a fixed, high resistance of muscle to passive stretch resulting from fibrosis of the muscles and joints, or from disorders of the muscle fiber resulting in LROM, for example, of a patient's arm or leg. In this regard, Webster's Dictionary defines “contracture” as “a permanent shortening (as of muscle, tendon and scar tissue) producing deformity or distortion.”
This first type of contracture is usually due to trauma, injury, or surgical intervention affecting the joint, as may be typical of sports injuries and the treatment thereof. As the injured tissue heals, edema, post trauma or surgically affected tissue regeneration and other natural healing processes result in the fusing together of what were, prior to the trauma, separate, pristine connective tissues, that is, the collagen fiber matrix (depicted diagrammatically in FIG. 1A of my prior patent), capable of easily gliding over one another, as is needed for normal joint movement and related muscle elongation.
However, post-trauma, this collagen fiber matrix becomes random and irregular (depicted diagrammatically in FIG. 1B of my prior patent), and neither elongates nor stretches compared to non-traumatized collagen fibers. This fusing-together or adhesion of connective tissue structures (e.g., ligaments, tendons, synovial membrane, fascia and fibrous joint capsules) is the result of the tissues being invaded by developing undifferentiated scar between adjacent tissue, thereby diminishing or preventing the mutual gliding after early healing of the trauma or post-surgical trauma has been accomplished.
Such fusing together of connective tissue is a leading cause of lags (a non-specific indictment of the motor system's failure to move the affected joint through the full available passive range) relating to tendon gliding, depending on their strategic placement in reference to structures crossing the joint. With limited mobility and associated extensor muscle atrophy, combined with the formation of adhesions and scar tissue in the form of a significantly increased number of joined fiber matrix junctions, the muscle fibers become shortened.
The restoration of full range of motion (ROM) where fibrosis of the muscle fiber with scar tissue and adhesions are present requires that the adhesions and scar tissue or fused fiber matrix junctions be “worked through” or broken to restore normal functional elongation or stretch. The term “no pain, no gain” (of increased range of motion) is associated with the process of breaking through joined or fused fiber matrix junctions to restore full elongation of the connective tissue, tendons and muscles associated with the trauma-affected joint.
Heretofore known orthotics are primarily designed to treat this first type of contracture, but have also been used to treat contractures caused by immobility and neurological dysfunction (described below). However, such orthotic devices are not, as far as is known by the present inventor, best suited for such additional purpose.
The second and very different type of contracture results from joint immobility—not joint-related trauma or surgical repair of a joint. Contracture resulting from immobility is simply a shortening and thickening of the connective tissue, tendons and muscles (depicted in FIG. 1C of my prior patent) that restrict the ROM of a joint. In such situations, the muscle fibers still retain their original uniform shape and there are no adhesions or scar tissue or significantly increased joined fiber matrix junctions to break through in order to restore full range of motion.
In contrast to trauma-caused contractures, contractures due to immobility do not need a “no pain, no gain” approach to restoring the normal range of motion, and, in fact, such an approach can actually do more harm than good. As mentioned above, the collagen fibers of a contracture due to immobility are simply shorter and thicker, and will respond to appropriate stretching techniques and motion of the joint to restore LROM. The stretching technique usually used for contractures caused by immobility is Range Of Motion (ROM) Therapy and the use of Low-Load Protracted Stretch/Stress (LLPS) or “extended stretch” static or dynamic orthotic devices.
According to authors Kenneth R. Flowers and Susan L. Michlovitz in their article titled “ASSESSMENT AND MANAGEMENT OF LOSS OF MOTION IN ORTHOPEDIC DYSFUNCTION” (published in Postgraduate Advances in PHYSICAL THERAPY, American Physical Therapy Association, 1988 II–VIII), Total End Range Time (TERT) in conjunction with LLPS is the key to restoring full ROM.
All contractures, whether caused by injury, surgery, or immobility, limit range of motion of the affected joint and make simple activities of daily living, such as eating and self-dressing, more difficult, if not impossible. Moderate to severe contractures can be debilitating, and can leave afflicted individuals bed-bound and unable to care for themselves in the most basic daily living tasks. Even mild contractures due to immobility can progress to severe contractures if proper intervention is not prescribed and implemented so long as the immobility continues.
A principal objective of my current invention is accordingly to provide more clinically effective orthotics that are an alternative to the known types of orthotics currently used to treat contractures caused by immobility and the ROM stretching technique. The main function of my new and more effective orthotic devices is to treat contracture due to immobility—not trauma related to surgery or injury.
The present inventor considers that TERT with Activity Stimulus Strategy (i.e., flexing)—not LLPS—is the key to predisposing tissue to elongation and restoring range of motion, where LROM is due to immobility or neurological dysfunction.
The clinical importance and value of orthotics disclosed in my prior patent are significant in that contractures and other hazards of immobility are one of the ten current highest health care costs in America that are totally preventable. This puts the health risks associated with immobility in the same category as cigarette smoking, alcohol and drug abuse, and automobile accidents in financial impact on American health care costs.
The orthotic devices disclosed in my prior patent provide more effective clinical treatment for LROM due to immobility by increasing the “stimulus of activity” of the affected tissue (connective and muscle fiber) rather than just holding the issue in moderately lengthened position (LLPS or “gradual extension” therapy). According to Brand (1984), “It is better not to use the word stretch for what should be long-term growth. If we want to restore normal length to a tissue that has shortened after disease (or disuse), we need to reverse the process and apply the stimulus of activity, or better, the stimulus of holding the tissue in the moderately lengthened position for a significant time.” According to Brand, it will then “grow” or lengthen. Flowers and Michovitz in the before-mentioned article theorize that the joint somehow senses or computes the total stress applied to it in any given direction over a period of time. It then stimulates a proportionate amount of biological activity, leading to a proportionate mount of remodeling of the stressed tissue. The total stress is a product of its intensity, frequency and duration. The crucial elements in this conceptual model are frequency and duration. Total stress equals intensity times frequency times duration.
My previously-disclosed orthotic devices increase the stimulus of activity relative to current orthotic devices which simply hold the limb and joint in an extended position for extended periods. Conceptually, patient outcomes should be more positive based upon an increased stimulus of activity as well as providing moderate stretch for a prolonged period with the new devices. The cycling or repeated extension and contraction of the joint by my previously-disclosed orthotics provides the additional benefits of motion (activity), increased lubrication of the tissues (production of synovial fluid) facilitating movement, and muscle re-education and diminished spasticity where neurological dysfunction is present (stroke, closed head injury, MS, etc.). The level of activity is higher with these devices when high tone, spasticity, or moderate to high contraction reflexes are present in the affected limb and joint. Thus my previously-disclosed devices are uniquely appropriate for contractures due to immobility where neurological dysfunction is present in the affected limb.
My prior patent discloses the use of a spring-type interconnection between upper and lower limb attachment members of a limb-type (arm-type and leg-type) orthotic. Such spring-type interconnections provide a torque to applied arms or legs that opposes muscle forces that cause contracture of the limb. Thus, when a contracted arm or leg is manually stretched to increase ROM, and is released after application of the orthotic to the limb, the limb muscles initially overcome the spring forces of the orthotic causing the limb to contract to or toward the initially contracted position. As the limb muscles then tire or relax, the spring forces (that is, torque) of the orthotic stretch or pull the limb back out to or toward the initially stretched position. The limb muscles then again take over and cause another limb contraction against the orthotic spring forces. As the limb muscles again tire or relax, the spring forces (that is, torque) of the orthotic stretch or pull the limb back out to or toward the initially stretched position. As this alternate limb contracting and stretching cycle is repeated, usually many times, (as depicted in attached FIG. 3) the ROM of the limb is gradually increased to that of the initially stretched position.
Although not specifically disclosed the spring force of the orthotic of my prior patent exhibits a typical spring force that increases in a generally linear manner with spring compression and tension. The present inventor has, however, subsequently discovered that an improvement can be made to my previously-disclosed orthotics.
It is thus a principal objective of the present invention to provide a limb-type orthotic having a spring force that initially increases with spring angle over an initial spring angle range, then peaks over an intermediate spring angle range and finally decreases over a final spring angle range, as depicted in FIGS. 3 and 4 of this application, so as to inhibit potentially injurious muscle spasms in the limb to which the present orthotic is attached.
In the various FIGS. identical elements and features are given the same reference numbers and corresponding elements and features for variation orthotic devices are given the original reference numbers followed by an “a” or “b” and so forth as appropriate.